Deflecting yoke



A. BLAIN April 1, 1941.

Filed Mar 3nventor l||I|l||||llllllllllllllllllllili lllllllllllllllllllllllllllllllllllllllll illllllllll Albert Blain Patented Apr. 1, 1941 DEFLECTIN G YGKE Albert Elain, Philadelphia, Pa., assignor to Radio Corporation of America, a corporation of Dela- Application March 21, 1940, Serial No. 325,130

4 Claims.

My invention relates to cathode ray deflecting means, and particularly to electromagnetic deflecting yokes designed to deflect a cathode ray both horizontally and vertically.

One of the objects of my invention is to provide an improved deflecting yoke which may be opened or split to permit positioning the yoke on the neck of a cathode ray tube without sliding it over the end of the tube.

A further object of my invention is to provide an improved deflecting yoke which extends a minimum distance radially from the associated cathode ray tube.

In a preferred embodiment of my invention, the horizontal deflecting coils are of the distributed type described in Tolson Patent No. 2,167,379, issued July 25, 1939, and assigned to the Radio Corporation of America. The vertical deflecting coils are wound on opposite sides of a cylindrical magnetic core, preferably made of iron wire, and connected with their fields in bucking relation. The iron core is split and each core half with its vertical deflecting winding set into one of the horizontal deflecting windings in nested relation.

The invention will be better understood from the following description taken in connection with the accompanying drawing, in which- Figure 1 is a side view of a cathode ray tube of the restricted neck type upon which there is mounted a deflecting yoke embodying my invention,

Figure 2 is a plan View of a deflecting yoke embodying my invention,

Figure 3 is a side view of the yoke shown in Fig. 2,

Figure 4 is a view taken in cross section on the line IV-IV of Fig. 3, and

Figure 5 is a view taken on the line VV of Fig. 4.

Referring to 1, my improved deflecting yoke, which is indicated at I, is shown mounted on a cathode ray tube 2 of the type having a constriction in the neck. The yoke 1 consists of the two halves Ia and lb whereby the yoke may be made to fit closely around the constricted portion. In Fig. 1, the yoke l is shown provided with a protective outside covering of cardboard or fiber not illustrated in the remaining figures.

The construction of the yoke is shown more clearly in Figs. 2 to 5, where the oppositely disposed horizontal deflecting coils are indicated at 6a and 6b. As previously stated, these coils are of the distributed type. Their ends preferably are upturned as shown in my copending application Serial No. 174,837, filed November 16, 1937, and assigned to the Radio Corporation of America.

The vertical deflecting coils indicated at la and lb are of the general type described in Maloff Patent No. 2,164,931, issued July 4, 1939, and assigned to the Radio Corporation of America, their main characteristic being that they are wound on opposite sides of a magnetic core 8 and connected in bucking relation. Therefore, their deflecting flux is at right angles to the deflecting flux of the horizontal deflecting coils.

The magnetic core 8 preferably is made of laminations such as soft iron wire, although a solid magnetic sleeve may be used if the resulting additional eddy current loss can be tolerated. In any case, the core 8 preferably is split into an upper half and a lower half so that the yoke comprises one-half having the windings 6a, and la and another half having the windings 6b and lb.

The core 3, if made of iron wire, or other laminations, may be held together with any suitable material, such as coil impregnating wax, styrol, or the like.

As clearly illustrated in the drawing, the vertical deflecting coils la and lb are nested in the horizontal deflecting coils 6a and 6b, respectively. For example, the under portion of the coil Ea sets into the central opening of the distributed coil to as shown in Fig. 4. As a result, the vertical deflecting coils la and 1b need not extend radially beyond the upturned ends of the horizontal deflecting coils whereby the dimension of the complete yoke measured radially from the center of the yoke may be comparatively small. This feature may be advantageous when the cathode ray tube is employed with certain types of optical systems for projection of a television picture appearing on the end of the tube where a large diameter deflecting yoke would intercept some of the light.

One of the features of the above-described deflecting yoke design is that the magnetic shell 8 functions as a magnetic core for the horizontal deflecting coils 6a and 5b as well as for the vertical deflecting coils. So far as the horizontal deflecting coils are concerned, the shell 8 corresponds to the outer magnetic shell described in the previously mentioned Tolson patent.

From the foregoing, it will be apparent that I have provided an improved deflecting yoke of small diameter and that I have also provided an improved yoke which may be split to permit its assembly on a cathode ray tube without sliding it over the end of the tube.

I claim as my invention:

1. A deflecting yoke comprising a pair of oppositely disposed horizontal deflecting coils, a magnetic shell or core surrounding said horizontal deflecting coils, and a pair of oppositely disposed vertical deflecting coils Wound on said core with each vertical deflecting coil located opposite a horizontal deflecting coil, said vertical deflecting coils being so connected that their magnetic fields are in bucking relation.

2. A deflecting yoke comprising a pair of oppositely disposed deflecting coils, a magnetic shell or core surrounding said deflecting coils, and a second pair of oppositely disposed deflecting coils wound on said core and positioned with each deflecting coil located opposite a deflecting coil of the first pair, said second pair or" deflecting coils being so connected that their magnetic 20 fields are in bucking relation, said core being split longitudinally into two halves with the lines of division for said halves occurring substantially half way between said second pair of coils.

3. A deflecting yoke comprising a pair of oppositely disposed distributed horizontal deflecting coils, each of said coils having an opening in the middle thereof, a magnetic shell or core surrounding said horizontal deflecting coils, and a pair of oppositely disposed vertical deflecting coils wound on said core and each vertical deflecting coil located opposite the said opening of a horizontal deflecting coil, said vertical defleeting coils being so connected that their magnetic fields are in bucking relation.

4. The invention according to claim 3 wherein said core is split into two halves with each half surrounding a horizontal deflecting coil.

ALBERT BLAIN. 

